1. Field of the Invention
This invention relates to a system for viewing an enlarged image on a screen. More particularly, the present invention discloses a new and improved viewing system which projects an enlarged image of a specimen or workpiece onto a moving lenticular screen where it can be viewed with a wide angle of vision.
2. Description of the Prior Art
Rotating screen optical projectors and systems for projecting enlarged images on screens are known. Rotating screen optical projection viewing systems, which are adapted to be mounted onto microscope stands in place of the ocular lens of a microscope, are also known.
Prior art rotating screen optical projection systems have required a long distance between the objective lens and the projection lens. To accomodate the substantially long distance between these lenses, the lenses are by necessity mounted separately and often require adjustment during manufacture and assembly and often require further adjustment when the objective lenses are being changed.
In order to accomodate a long optical path from the objective lens to the projection screen, the prior art systems have located the work station and/or the viewing screen at an undesirable distance from the person viewing the screen. Due to the requirement of a long optical path, some of the components and reflective surfaces required to bend the optical path are also located at undesirable positions within the prior art housings of the viewing system. In order to contain the prior art viewing screen in a compact housing, it was often necessary to place the viewing screen in the optical path at an angle which was tilted from the normal axis so great as to cause image distortion.
The prior art optical viewing systems often serve as a substitute for a microscope or a closed loop circuit television set used for viewing workpieces or specimens. When viewing a television screen, the operator or observer usually needs the workpiece at a convenient location for manual adjustment. The closed loop television screen is often located at a position which requires the observer to look to one side or the other of the workpiece and at an elevation which is not normal or restful. When the optical viewing system is placed on a microscope's stand in the prior art systems, the viewing screen location is dictated by the optical path of the system. Thus, the viewing screen has not been located at a comfortable or preferred restful position but has been located at an elevation predicted by the optical system and has not provided any adjustment for locating the viewing height.
Some of the prior art optical rotating screen projection viewing systems have not employed an optimum optical path and thus, have produced either bright reflected light spots or shadows on the viewing screen which causes the image to be illuminated nonuniformly.
Further, when the prior art optical viewing systems employed a rotating projection screen as an attachment to replace a microscope eyepiece, the amount of light that was usually available from the microscope light source to illuminate the workpiece or the specimen was spread over the large area of the projection screen which attenuated and reduced the brilliance of the image on the screen. Prior art optical projection viewing systems which employed rotating screens were vibration prone when adapted to be mounted onto a microscope designed to support eyepieces only. Vibration in such systems cause the image on the screen to be unstable.
It would be desirable to provide an optical projection viewing system which has a moving lenticular screen located at an optimum distance from the eye of the observer and having an adjustment which permits the angle of view of the screen to be adjusted to the eye height of the observer. Further, it would be desirable to provide a more compact and stable optical projection viewing system which permits the operator to make X, Y and Z adjustments manually with a single hand.